Above: Global TEC and L1 range error
What are these?
Affected by solar activity, Total Electron Content (TEC) describes the total number of free electrons present within one square meter between two points (i.e. between the receiver and satellite). The larger the TEC quantity, the longer the delay in a received GNSS signal. This leads to positional errors in GPS readings amounting to tens or even hundreds of meters in severe circumstances.
The maps above shows the latest TEC values, updated every five minutes.
Credits: as shown on the images.
Click on the images to open source websites.